
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author fe500728
 */
public class Identification extends HttpServlet {

    String login = "";

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {


            response.setContentType("text/xml");
            OutputStream os = response.getOutputStream();
            OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8");
            PrintWriter pw = new PrintWriter(osw);





        } finally {
            out.close();
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //processRequest(request, response);
        String fPathOnline = request.getRealPath("index.jsp").replace("index.jsp", "online.xml");
        PrintWriter out = response.getWriter();
        try {
            login = request.getParameter("login");
            
            if (login != null) {
                if (login.length() > 0) {
                    if (isLoginExistant(login,fPathOnline)) {
                        out.print("KO");
                    } else {
                        addUser(login,fPathOnline);
                        out.print("OK");
                    }
                } else {
                    out.print("KO");
                }
            } else {
                out.print("KO");
            }
        } finally {
            out.close();
        }
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);


    }

    /**
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

    public boolean isLoginExistant(String log,String fPathOnline) {

        try {

            boolean isNotLoged = false;

            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document doc = db.parse(fPathOnline);
            doc.getDocumentElement().normalize();


            NodeList nodeLst = doc.getElementsByTagName("users").item(0).getChildNodes();


            for (int s = 0; s < nodeLst.getLength(); s++) {

                Node fstNode = nodeLst.item(s);

                if (fstNode.getNodeType() == Node.ELEMENT_NODE) {


                    if (fstNode.getTextContent().equals(login)) {
                        isNotLoged = true;
                    }


                }
            }

            return isNotLoged;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }


    }

    public void addUser(String name, String fPathOnline) {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        try {
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document doc = db.parse(fPathOnline.trim());

            Node n = doc.getElementsByTagName("users").item(0);
            Node element = doc.createElement("user");
            ((Element) element).setTextContent(name); //setAttribute("user", "value");
            n.appendChild(element);

            Source source = new DOMSource(doc);


            File file = new File(fPathOnline.trim());
            file.createNewFile();

            doc.setDocumentURI(doc.getDocumentURI().trim());
            file.setWritable(true);
            Result result = new StreamResult(file.toURI().getPath());

            
            Transformer xformer = TransformerFactory.newInstance().newTransformer();
            xformer.transform(source, result);

            
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}